Devices for measuring electrostatic capacitance of a capacitor are disclosed, for example, in Japanese Patent Laying-Open Nos. 56-107170 (Patent Literature 1) and 2-271266 (Patent Literature 2). The device disclosed in Japanese Patent Laying-Open No. 56-107170 includes a power supply and a DC current measuring device. The power supply increases voltage with time at a known constant rate. The power supply and the DC current measuring device are connected in series to terminals of a capacitor. From the measured current value, electrostatic capacitance of the capacitor is calculated.
The device disclosed in Japanese Patent Laying-Open No. 2-271266 includes a DC power supply, a resistor connected between the DC power supply and a capacitor, a current detecting circuit for detecting a current flowing through the resistor, an integrating circuit for integrating charging current detected by the current detecting circuit, and an operation output unit. The operation output unit calculates electrostatic capacitance of the capacitor based on the integrated value obtained by the integrating circuit and the voltage across the capacitor terminals.